The subject application relates generally to a header for use with agricultural harvesters. In particular, the subject application relates to a dual conveyor infeed for a header of a combine harvester.
The headers for agricultural harvesters, such as combines, that harvest crops may assume a variety of configurations depending on the crop being harvested. In any case, harvester headers include devices for conveying harvested crop to a feederhouse after which the crop undergoes additional processing. After the crop is cut by a cutting knife or other cutting mechanism, it is typically gathered for example by a reel that transports the crop to a header conveyor device which may include one or more augers or belt conveyors. Generally, the header conveyor device includes an opposed set of lateral augers (as in an auger header) or belts (as in a draper header) which transfer crop from lateral ends of the header toward a feederhouse opening located at a central region of the header. The feederhouse extends generally perpendicular to the conveyor augers or belts. In draper headers, for example, a central infeed belt and a central infeed auger are provided in order to impel the crop flowing from the lateral belts into the feederhouse opening. The central infeed auger spans the feederhouse opening and has helical vanes which terminate at the opposite ends of the infeed auger.
It has been observed that during operation of an agricultural harvester having a header equipped with a feederhouse infeed auger that the outer ends of the rotating infeed auger vanes interfere with the laterally incoming crop flow. This interference between the infeed auger vanes and the incoming crop flow causes crop to collect at the opposite ends of the infeed auger. The collected crop in turn results in an inconsistent flow of crop being fed by the infeed auger to the feederhouse. The inconsistent crop flow may include “dead zones” where little or no crop is present and is not actively being transported or moved and heavy zones where excessive crop is present. Grain processed through the header can accumulate at the dead zones or voids and thereby negatively impact the overall efficiency and operation of the combine during harvesting operations. Furthermore, in conventional combine harvesters, due to the overall cylindrical shape of the header's cross auger and the feederhouse feed drum, there exists a region or void space between them at or below their respective central rotational axes that grain is not actively transported. Because of this void and lack of any active transport means between the cross auger and feeder drum grain flow may become inhibited and back up. That is, grain is only passively conveyed between the cross auger and the feeder drum through the void in conventional combines. Such inconsistent crop flow results in inconsistent demands being placed on the entire harvesting machine. Therefore, machine settings including engine speed and other parameters must be continually adjusted to accommodate for the effects of the inconsistent flow of crop which may lead to more energy being used by the harvester than might otherwise be necessary to harvest the crop. Furthermore, some of the crop which collects at the outer ends of the infeed auger may be forced over the auger such that it is not picked up by the feederhouse conveyor and is left in the field, thereby resulting in a less than optimal crop harvest.